The present invention relates to a card-like wireless communication device as set forth in the preamble of claim 1. The invention also relates to a method in the manufacture of an expansion card for an electronic device as set forth in the preamble of claim 7. The invention also relates to an expansion card for an electronic device as set forth in the preamble of claim 9.
According to prior art, various electronic devices, such as portable personal computers (PC) are often equipped with an expansion card interface slot, to which a standardized expansion card can be connected. These expansion cards are intended to form a functional unit with the PC. The expansion cards can also contain the radio parts of a wireless communication device, including an antenna, wherein the PC can, by means of this card-like wireless communication device, communicate with other devices or a communication network, such as the GSM network (Global System for Mobile Communication). The antennas are used for the transmission and reception of radio-frequency signals, and the signals are transmitted between the radio part and the antenna of the wireless communication device normally by means of wires and connectors.
One known expansion card is a PC card complying with the PCMCIA standard (Personal Computer Memory Card International Association). PC cards are designed to be inserted fully inside a PC, but so-called extended PC cards are longer than ordinary PC cards. These extended PC cards are placed partly outside the PC, wherein the thickness and design of the PC cards may vary in this part to be placed outside the PC. In a manner known per se, this part usually contains the separate antenna of the wireless communication device.
One known card-like wireless communication device comprising a transceiver with its antenna is the Nokia Cellular Card Phone, i.e. a card phone that can be connected to expansion card connections of PC card types 11 and 11 complying with the PCMCIA standard. One embodiment of the card phone according to prior art is shown in FIG. 1, and the operation of the card phone is described in more detail in e.g. U.S. Pat. No. 5,809,115. In the card phone, the antenna part containing the antenna is placed outermost in the part located outside the PC, this part being connected to the card-like part of the card phone that is placed at least partly inside the expansion card interface slot. Other known card-like wireless communication devices are presented in U.S. Pat. No. 5,628,055, disclosing a separate turnable antenna that can be attached to the end of the card, and U.S. Pat. No. 5,361,061, disclosing a foldable antenna pivoted on the top surface of the end of the extended card.
Other known expansion cards include e.g. a so-called CompactFlash (CF) card complying with the CFA standard (Compact Flash Association). For example for these CF cards, there are adapters of the size of the PCMCIA card, in which the CF card is placed for a PCMCIA interface. Also known are expansion cards for a wireless local area network (WLAN). Other expansion cards include also a so-called Miniature Card, whose size is only 38 mmxc3x9733 mmxc3x973.5 mm, as well as a so-called SmartMedia card, whose size is only 45 mmxc3x9737 mmxc3x970,76 mm, and a so-called MultiMediaCard (MMC), whose size is only 32 mmxc3x9724 mmxc3x971.4 mm.
One drawback in known card-like wireless communication devices is that during the use and when placed in the expansion card interface slot, particularly the antenna structure forms a part protruding from the electronic device. Furthermore, the interfaces often comprise a protective cover to protect the expansion card, which must be kept open when the antenna structure extends outside the electronic device. The protruding part of the antenna structure and the protective covers may stick in something particularly during the transportation and use of the device, as well as cause damage. Therefore, the card must be removed after the use and be stored separately from the device.
It is an aim of the present invention to eliminate the above-mentioned drawbacks by means of a card-like wireless communication device according to the invention. The card-like wireless communication device of the invention is characterized in what will be presented in the characterizing part of claim 1. The method in the manufacture of an electronic device according to the invention is characterized in what will be presented in the characterizing part of claim 7. The expansion card for an electronic device according to the invention is characterized in what will be presented in the characterizing part of claim 9.
The essential principle of the invention is to use a bendable, flexible strip-like antenna structure. In other respects, the card-like wireless communication device constitutes preferably a compact unit with standard dimensions. When unfolded, the antenna structure extends outside the electronic device, but the protruding part is a flexible, preferably solid part which is flexible and bendable upon touching, wherein the risk of damage is reduced, particularly in comparison with rigid, elongated antenna structures.
When the strip is folded against the card, the card does not need to be removed from the electronic device for the time of transportation, wherein it is faster to take the device and the card into use. At the same time, the insertions and removals of the card into and from the interface are reduced, wherein the wear and malfunction of the interface are reduced. Thanks to the flexible structure, the forces directed to the antenna structure are not transmitted to the attachments of the strip, wherein damage to the attachments and the card itself is avoided. This has also the advantage that the attachments are simple and small-sized, wherein the antenna structure according to the invention also utilizes as little space inside the card as possible, thereby vacating space for other components. Furthermore, the strip with its attachments is also easy and inexpensive to manufacture. It is often advantageous that the antenna is brought farther away from the electronic device to reduce the effect of electromagnetic interference, which is now made possible by the invention in a safe way.
The flexible antenna can be bent against the card, wherein it fits preferably entirely in the expansion card interface slot, preferably at least under a closed protective cover that is possibly provided to protect the interface. A particular advantage of the invention is that the strip can be used for pulling the card out from the expansion card interface slot, wherein a short card can be used also in devices with no mechanism for pushing the card out.
Another particular advantage of one embodiment of the invention is that when the antenna structure comprises two transverse antenna elements, good electrical functioning of the antenna in different position of the strip can be secured in such a way that a first antenna element is placed further away from the outer surface on the strip or at the outermost end of the unfolded strip, and a second antenna element is placed e.g. close to the outer surface. Thus, when the strip is bent against the card and placed in the expansion card interface slot, the second antenna element is exposed in the opening of the interface and thereby outermost in the direction of the cover surface and the bottom surface.
The invention is applicable for use particularly in electronic devices which are suitable for networks of low power radio frequency (LPRF) to be used as wireless local area networks, such as piconets, wherein the range of operation is normally from 0.1 to 10 m, even 100 m if necessary. These wireless networks operate in the ISM range at the frequency of 2.4 GHz. The invention is suitable for use in so-called Blue-tooth technology, whereby cables can be replaced by the radio channel e.g. between PC devices and peripheral equipment.